Brush head for toothbrush

ABSTRACT

A head for a toothbrush including a neck and, first and second sets of one or more bristles each. The first and second sets are indirectly supported by the neck and movable relative to each other such that at least one component of this relative movement causes the bristle(s) of the first set to be raised and/or lowered relative to the bristle(s) in the second set. The first and second sets of bristles both are movable relative to the neck.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/430,280 filed on May 9, 2006 which is a continuation of U.S. patentapplication Ser. No. 10/697,206 filed on Oct. 30, 2003 which is acontinuation of U.S. patent application Ser. No. 10/456,769 filed onJun. 6, 2003 (U.S. Pat. No. 6,760,946) which is a continuation of U.S.patent application Ser. No. 09/425,423 filed on Oct. 22, 1999 (U.S. Pat.No. 6,574,820).

FIELD OF THE INVENTION

The invention relates generally to the field of oral care, and inparticular to toothbrushes. More specifically, the invention relates toa brush head for a toothbrush.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 5,577,285 (the '285 patent) discloses an electrictoothbrush with a rotary bristle supporting structure. In one embodimentof the invention shown in FIG. 6, the brush head is driven such that anouter ring of bristles 45 a and an inner ring of bristles 45 b are movedin an alternating rotary motion in opposite directions. While such anarrangement is beneficial for cleaning, for example, the bucal orlingual tooth surfaces, the lack of motion of any of the bristles in anup and down pattern results in a less than optimal cleaning of theinter-dental tooth surfaces.

FIG. 9 of the '285 patent discloses an additional embodiment of theinvention in which all of the bristles 45 are rotated about an axis 54while also being moved in an up and down motion parallel to this axis.This embodiment will provide enhanced cleaning of the inter-dental toothsurfaces. However, the fact that all of the bristles are moved up anddown limits the depth of penetration that the bristles can obtainbetween the teeth. This is because while some of the bristles are tryingto penetrate between the teeth, others are pressing against, forexample, the bucal tooth surface, thus limiting the motion of the brushhead towards the teeth.

SUMMARY OF THE INVENTION

The present invention is directed to overcoming one or more of theproblems set forth above. Briefly summarized, according to one aspect ofthe present invention, a head for an electric toothbrush, includes afirst bristle support which is rotatable about an axis and a pluralityof first bristles extending from the first bristle support. A secondbristle support includes a plurality of second bristles extending from asurface of the second bristle support at an acute angle to the surface.

These and other aspects, objects, features and advantages of the presentinvention will be more clearly understood and appreciated from a reviewof the following detailed description of the preferred embodiments andappended claims, and by reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an electric toothbrush head attached to a brushhandle/drive;

FIG. 2 is an exploded side view of the toothbrush head;

FIG. 3A is a side view of the head with a central bristle in a retractedposition;

FIG. 3B is a side view of the head with a central bristle in an extendedposition;

FIG. 4 is a top plan view of a second embodiment of an electrictoothbrush head;

FIG. 5 is a sectional view of FIG. 4 taken along the lines 5-5;

FIG. 6 is a sectional view of FIG. 5 taken along the lines 6-6;

FIG. 7 is a sectional view of FIG. 5 taken along the lines 7-7;

FIG. 8 is a sectional view similar to FIG. 5 of a third embodiment ofthe invention;

FIG. 9 is a sectional view of FIG. 8 taken along the lines 9-9;

FIG. 10 is a sectional view of FIG. 8 taken along the lines 10-10;

FIG. 11 is a sectional view of FIG. 8 taken along the lines 11-11;

FIG. 12 is a sectional view of FIG. 8 taken along the lines 12-12;

FIG. 13 is a perspective view of a fourth embodiment of a toothbrushhead; and

FIG. 14 is a front view of the toothbrush head of FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

Beginning with FIG. 1, an electric toothbrush head 10 includes a neck 12which is connected to a bristle support 14. Bristles 16 on support 14are oscillated in a rotary movement through an arc of between about +−15to 90 degrees, more preferably +−20 to 50 degrees as in a conventionalelectric toothbrush.

FIG. 2 shows support 14 in an exploded side view. An interdental probe18 is secured to a slider core 20 in the center of bristles 16. Probe 18can be a single large bristle or a tuft of much smaller bristles.Alternatively, core 20 can be enlarged to accommodate a plurality ofprobes (not shown), one of which may be positioned in the center of thecore (as in FIG. 1), with the remainder of the probes being positionedon the core away from its center.

A pair of cam follower pins 22 are secured to opposite sides of thelower portion of core 20. Core 20 is positioned inside of a brush base24 such that pins 22 are forced to ride along respective cam tracks 26as well as respective vertical slider tracks 28 (one slider track ishidden behind the other). A retaining pin 30 rides in a track 32 toretain base 24 within a housing 34. A guide/rotation pin 36 passesthrough a hole in the bottom of housing 34 and is secured to base 24.

Operation of support 14 will be explained with reference to FIGS. 2, 3Aand 3B. Pin 36 is oscillated about its long axis by a drive mechanism(not shown) in neck 12. The drive mechanism can be of conventionaldesign. Oscillation of pin 36 causes brush base 24 and bristles 16 tooscillate in a rotary pattern. Pin 30 retains base 24 within housing 34.Oscillation of base 24 causes core 20 and probe 18 to oscillate with thebase because pins 22 ride in track 28 of the base. Pins 22 also ride inrespective tracks 26 in the housing, thus causing core 20 and probe 18to move up and down relative to bristles 16 during oscillation of brushbase 24. FIGS. 3A and 3B show that a preferred extension of probe 18from its lowest to highest position is about 5 mm.

In an alternative embodiment, all of bristles 16 are eliminated, leavingonly probe 18 for cleaning teeth. This embodiment would be usedprimarily for cleaning interdental spaces, not for cleaning the othersurfaces of teeth.

Turning to FIGS. 4-7, a second embodiment of the invention will bedescribed. A brushhead 40 can be attached to a handpiece (not shown) ofan electric toothbrush. A driveshaft (not shown) protrudes out of thehandpiece and can effect an oscillating rotation. Brushhead 40 includesa tube 42 in which a shaft 44 is located. The rear end of tube 42 fitsinto the housing (not shown) of the handpiece. Shaft 44 engages thedriveshaft of the handpiece. A pin 46 is press fitted into shaft 44. Pin46 can rotate at its free end in a bearing hole 48 in a front part 50 oftube 42. Axis 52 of pin 46 coincides with the axis of the driveshaft ofthe handpiece.

A pivot 54 can rotate in a bearing hole 56 situated in front part 50 oftube 42. Pivot 54 is retained in hole 56 by a ring 58. A brush base 60is press fitted onto pivot 54. Brush base 60 has holes 62 in which tuftsof bristles 64 are secured. A cross pin 66 is welded onto the free endof pivot 54. Both ends of cross pin 66 retain brush base 60 on pivot 54by interaction with a shoulder 68 of the brush base. The central part ofcross pin 66 is placed in a bearing hole 70 of a rocker 72. Rocker 72can swivel about cross pin 66 and contains holes 74 in which tufts ofbristles 76 are secured.

Shaft 44 includes a bearing hole 78 in which a drive rod 80 can move.The distance between axis 52 of pin 46 and an axis 82 of drive rod 80 isa radius r1. A stud 84 is welded onto the free end of drive rod 80. Thedistance between an axis 86 of pivot 54 and an axis 88 of stud 84 is aradius r2. Stud 84 can move in a bearing seat 90 in brush base 60. Atone end of stud 84 is carried a ball 92 which can move in a cylindricalslot 94 in rocker 72.

When shaft 44 is oscillated about axis 52 through an angle of +−alpha 1about pin 46, two different motions are induced. First, brush base 60and rocker 72 are oscillated in a rotating manner through an angle of+−beta 1 about pivot 54 in bearing hole 56. This oscillating rotationcauses bristles 64 to wipe plaque off teeth like a broom. Second, rocker72 is oscillated in a rotating manner through an angle of +−gamma 1about cross pin 66 in bearing hole 70. Oscillation of rocker 72 aboutpin 66 causes bristle tufts 76 to loosen plaque like a chisel. Twocycles of oscillation of rocker 72 about pin 66 occur for every onecycle of oscillation of base 60 and rocker 72 about pivot 54. Therelations between the oscillation angles alpha 1 to beta 1 and alpha 1to gamma 1 depend only on radii r1 and r2.

Referring to FIGS. 8-12, a third embodiment of the invention will bedescribed. The third embodiment modifies the relationship between theoscillation angles, primarily to increase the gamma angle of theoscillating rotation of rocker 72. The basic features of the thirdembodiment remain unchanged from the second embodiment. The maindifference is in the location of the drive rod.

In the mid-position of the oscillating rotation of a shaft 100, a driverod 102 is located at a distance e from a median plane 104 of abrushhead 106. A stud 108 is welded laterally on a free end of drive rod102 with a distance e between the center-lines. Stud 108 is movable in abearing seal 110 of a brush base 112. When a drive shaft 114 is in amid-oscillation position, stud 108 is in a median plane 116 of brushbase 112. Drive rod 102 can move in a bearing hole 118 in shaft 114.Bearing hole 118 is situated in the distance e from median plane 104 ofshaft 114 when the shaft is in its mid-oscillation position.

When shaft 114 is oscillated about median plane 104 through an angle of+−alpha 1, two different motions are induced. First, brush base 112 androcker 72 are oscillated in a rotating manner through an angle of +−beta2 which is smaller than +−beta 1 about axis 120. Second, rocker 72 isoscillated in a rotating manner through an angle of +−gamma 2 which isbigger than +−gamma 1 about cross pin 66. The relations between theoscillation angles alpha 1 to beta 2 and alpha 1 to gamma 2 depend onradii r1 and r2 as well as on the distance e.

In embodiments 2 and 3 of the invention, one component of the rockingmotion of rocker 72 causes bristles 76 to move up and down (i.e.substantially parallel to pivot 54) relative to bristles 64.

FIGS. 13 and 14 disclose a toothbrush head 130 which is similar infunction to the head of FIG. 4. The major difference is that tufts ofbristles 132 on a pivot bar 138 are tilted away from the perpendicular(to the top surface 140 of the pivot bar 138) at an angle 134 of betweenabout 1-20 degrees. Preferably the bristles 132 are tilted along thedirection of oscillation of bristles 136 on a brush base 142. Suchtilting of bristles 132 provides better interdental penetration duringthe respective upstrokes of pivot bar 138, particularly for the tuft(s)on bar 138 which are being moved by head 130 in the tilt direction. Itis preferable that tufts of bristles on both sides of bar 138 have thesame tilt angle and are tilted in the same direction (i.e. in the sameplane). Alternatively, tufts of bristles on opposite sides of the barcan be tilted in opposite directions. As shown in FIGS. 13 and 14, whenpivot bar 138 is oscillated relative to brush base 142, the top surface140 of pivot bar 138 and the top surface 144 of brush base 142 arecapable of lying in substantially a same plane (when pivot bar 138 isaligned with brush base 142) during the operation of the electrictoothbrush.

The invention has been described with reference to several embodimentsincluding a preferred embodiment. However, it will be appreciated thatvariations and modifications can be effected by a person of ordinaryskill in the art without departing from the scope of the invention.

1. A head for an electric toothbrush, comprising: a first bristlesupport which is rotatable in an oscillating manner about an axis; aplurality of first bristles extending from a surface of the firstbristle support, all of the first bristles extending from the firstbristle support extending in a perpendicular direction from the surfaceof the first bristle support; a second bristle support pivotally mountedon said first bristle support; and a plurality of second bristlesextending from a surface of the second bristle support at an acute angleto the surface, wherein at least some of the second bristles are angledaway from at least some of the first bristles in the direction ofoscillation of the first bristles.
 2. The head of claim 1, wherein thebristles on opposite sides of the second bristle support are angled inthe same direction.
 3. The head of claim 2, wherein the bristles onopposite sides of the second bristle support are angled in oppositedirections.
 4. A toothbrush head, comprising: a first bristle holder,the first bristle holder having a first bristle face supporting a firstbristle field; a second bristle holder having a second bristle facesupporting a second bristle field, wherein the first bristle field isdisposed at least in part within the second bristle field and is movablebetween a first position and a second position; and wherein the firstbristle field comprises a plurality of first bristle tufts which form anangle with the first bristle face of the first bristle holder.
 5. Thetoothbrush head of claim 4, wherein: at least a portion of the firstbristle face and the second bristle face are coplanar in the firstposition and at least a portion of the first bristle face and the secondbristle face are non-coplanar in the second position.
 6. The toothbrushhead of claim 4, wherein: the second bristle field comprises a pluralityof second bristle tufts which are substantially perpendicular to thesecond bristle face of the second bristle holder.
 7. The toothbrush headof claim 6, wherein: the first bristle tufts form an acute angle withthe first bristle face of the first bristle holder.
 8. The toothbrushhead of claim 6, wherein: at least some of the first bristle tufts aretilted away from the perpendicular to the first bristle face at an angleof about 1 to 20 degrees.
 9. The toothbrush head of claim 5, wherein:the first bristle holder is pivotally attached to the second bristleholder.
 10. The toothbrush head of claim 9, wherein: the first bristletufts at opposite ends of the first bristle holder are tilted in thesame direction.
 11. The toothbrush head of claim 9, wherein: the firstbristle tufts at opposite ends of the first bristle holder are tilted inopposite directions.
 12. The toothbrush head of claim 9, wherein: thefirst bristle holder has a central section which is pivotally connectedto the second bristle holder, a first section and a second section atopposite ends of the first bristle holder, and wherein the first bristletufts on the central section are substantially perpendicular to thefirst bristle face and the first bristle tufts on the first and secondsections are tilted at an angle relative to the first bristle face. 13.The toothbrush head of claim 12, wherein: the first bristle tufts forman acute angle with the first bristle face of the first bristle holder.14. The toothbrush head of claim 12, wherein: the first bristle tufts onthe first and second sections of the first bristle holder are tilted inthe same direction.
 15. The toothbrush head of claim 12, wherein: thefirst bristle tufts on the first and second sections of the firstbristle holder are tilted in opposite directions.
 16. The toothbrushhead of claim 4, further comprising a shaft operatively connected to thesecond bristle holder.
 17. The toothbrush head of claim 9, wherein thesecond bristle holder is mounted for oscillation on the toothbrush head.